Pages

Sunday, August 26, 2012

Marc Lewis, Ph.D. - Addiction as Self-Medication

This brief post at the Psychology Today blog, Addicted Brains (A neuroscientist examines life on drugs) by Marc Lewis, Ph.D., looks at the "self-medication" model of addiction, the perspective that most addictions are based in efforts to numb feelings that are perceived as too overwhelming to experience. This is a model to which I adhere, mostly based on my own experience.

A
while back I promised to survey the three most common models of
addiction—disease, choice, and self-medication—and say something about
the advantages and disadvantages of each. I got hung up on the choice
model for a few posts: there’s so much there to think about. But now
let’s look at self-medication as the essence of addiction.

The
self-medication model seems to be the kindest of the three. It has the
advantage of the disease model, in absolving the addict of excessive
blame, but it has the additional advantage of avoiding the stigma of
“disease” and all that goes with it. In fact, it gives control (agency)
back to the addict, who is, after all, acting as his or her own
physician. Whereas the disease model places agency in the hands of
others and casts the addict as a passive victim. Furthermore, the
self-medication model just might be the most accurate of the three.

The idea is simple: trauma
is the root cause. Trauma includes abuse, neglect, medical emergencies,
and other familiar categories, but it also includes emotional abuse,
and above all loss. Loss of a parent during childhood or adolescence can take many forms, including divorce, being sent away from home (in my case) or the shutting down of one or both parents due to depression or other psychiatric problems. Trauma is often followed by post-traumatic stress disorder (PTSD), which includes partial memory loss, intrusive thoughts, anxiety and panic
attacks, avoidance of particular places, people, or contexts, emotional
numbing or a sense of deadness, and overwhelming feelings of guilt or shame.
But if that’s not bad enough, PTSD is about 80% comorbid with other
psychiatric conditions—depression and anxiety disorders being chief
among them.

A famous study
using a huge sample (17,000) looked at Adverse Childhood Experiences
(ACEs) in relation to subsequent physical and mental problems. The
results of the study are nicely summarized in the Sept. 25/2011 issue of The Fix.
Take-home message: the relationship between trauma and addiction is
unquestionable. An ACE score was calculated for each participant, based
on the number of types of adverse experience they reported during
childhood or adolescence. The higher the ACE score, the more likely
people were to end up an alcoholic, drug-user, food-addict, or smoker
(among other things). Here are two graphic examples:

These figures, which are likely to be low estimates, show a 500% increase in the incidence of adult alcoholism,
and a 4,600% increase in the incidence of IV drug use, predicted by
early adverse experiences. Despite criticisms of the study, based mostly
on retrospective self-reporting, these correlations are huge and they
are meaningful, and follow-up prospective studies are finding similar
results.

So how does self-medication work? There must be something about PTSD, depression, and anxiety that gets soothed by drugs, booze, binge-eating,
and other addictive hobbies. Again, it’s not complicated. PTSD,
depression, and anxiety disorders all hinge on an overactive
amygdala—one that is not controlled or “re-oriented” by more
sophisticated (and realistic) appraisals coming from the prefrontal
cortex and anterior cingulate cortex (ACC). That traumatized amygdala
keeps signalling the likelihood of harm, threat, rejection, or
disapproval, even when there is nothing in the environment
of immediate concern. In fact, this gyrating amygdala lassos the
prefrontal cortex, foisting its interpretation on the orbitofrontal
cortex (and ventral ACC) rather than the other way around (which we
might loosely call emotion regulation). The whole brain is dominated by limbic imperialism—making it a less-than-optimal neighbourhood in which to reside.

At
the very least, drugs, booze, gambling and so forth take you out of
yourself. They focus your attention elsewhere. They may rev up your
excitement and anticipation of reward (in the case of speed, coke, or
gambling) or they may quell anxiety directly by lowering amygdala
activation (in the case of downers, opiates, booze, and maybe food). The
mechanisms by which this happens are various and complex. But addicts
and ex-addicts (like me) know what it feels like. If we find something
that relieves the gnawing sense of wrongness, we take it, we do it, and
then we do it again.

So, according to the self-medication model,
addictive behaviours “medicate” depression, anxiety, and related
feelings. But is that the whole story? I don’t think so, and I’ll get
into why in my next post.